Ligaments are the fibrous tissue that connects bones to other bones within the body. When ligaments are damaged, surgical reconstruction can be necessary, as the ligaments may not regenerate on their own. A number of surgical procedures exist for re-attaching ligaments, or other soft tissue, to bone. One example is the knee 100 shown in FIG. 1, which includes anterior and posterior cruciate ligaments 102, 104 extending from the head of the tibia 106 to the intercondylar notch of the femur 108. These ligaments operate to prevent forward and backward relative motion between the two bones. When ruptured (e.g., as can happen in strenuous athletic movements), surgical reconstruction can be necessary.
Tears in the cruciate ligaments of the knee can be repaired using a ligament graft taken from a cadaver (i.e., an allograft) or from a patient's own tissue (i.e., an autograft). Reconstruction procedures generally involve forming a hole in both the femur and tibia, and then securing opposite ends of the ligament graft in these holes. In one cruciate ligament repair procedure, a ligament graft is associated with a surgical implant and secured to the femur. A common femoral fixation means includes an elongate “button,” sometimes referred to as a cortical button. The cortical button is attached to a suture loop that is sized to allow an adequate length of the soft tissue graft to lie within the femoral tunnel while providing secure extra-cortical fixation.
Existing devices and methods can be limited because they do not always provide the desired strength or adjustability. In some instances for example, one or more knots tied to help maintain a location of the suture loop with respect to a cortical button, and thus the graft associated therewith, can loosen or slip. Thus, even if a ligament graft is disposed at a desired location during a procedure, post-operatively the circumference of the loop can increase, causing the graft to move away from the desired location. Further, it can be desirable to limit the number of knots used in conjunction with such devices, because of the potential for the knots loosening and because the additional surface area of the knots can increase the risk of trauma to surrounding tissue. Still further, existing devices and methods also lack adjustability in many instances. For example, in procedures in which multiple ligament grafts are associated with the cortical button, it can be difficult to control placement of one ligament graft without also moving the other ligament graft.
Accordingly, there is a need for improved graft fixation devices and methods for use in repair and reconstruction procedures that include, for example, the cruciate ligaments of the knee. In particular, there is a need for devices and methods for positioning and securing ligament grafts that provide increased strength and adjustability while minimizing the number of knots used.